Amplitude squeezing with a Fabry–Perot semiconductor laser: existence of an optimum biasing condition

Abstract

The effect of gain suppression on amplitude squeezing with a Fabry-Perot semiconductor laser is studied with a semiclassical model. A strong decrease of the internal amplitude noise and an optimum biasing point with minimum amplitude noise are demonstrated. Small gain nonlinearities improve external compression.

Optical corpuscular theory of semiconductor laser intensity noise and intensity squeezed-light generation

“…For quiet pumping under the same conditions the laser's internal noise decreases, as expected, with the emitted power, and a maximum reduction of 50% is obtained [1][2][3][4] :…”

“…The laser's external noise increases in the presence of gain suppression. 4,14,22 This result is explained by the decrease in the correlation between the internal fluctuations and the partition-noise forces at the laser facets and by the reduction in internal noise. Figure 7 shows the shot-noise-normalized external noise as a function of P when the laser is pumped high above threshold.…”

“…As for the linear gain approximation, the internal noise is reduced by a factor of 2 at high power when the laser is quietly pumped, but whatever the conditions of pumping are, the internal photon noise is squeezed and strongly reduced. 4 For external photon noise under normal pumping conditions the situation is quite different. The external noise is given for a high emitted power and at low frequency by…”

“…This result is in complete agreement with previously published results. 4,22 Under quiet pumping conditions the influence of gain suppression is the opposite. In this case the shot-noisenormalized external noise at high emitted power and low frequency is given by…”

“…3 A recent semiclassical model introduced an additive Langevin noise force linked to vacuum fluctuations and to nonresonant loss. 4 The semiclassical theory of semiconductor laser noise considers the spontaneous-emission fluctuations as the major noise source. A description of semiconductor laser noise without quantification of the optical field was recently proposed by Arnaud.…”